AutoCAD DXF

The GDB library supports AutoCAD vectors (version 2004 or less) in the form of a DXF (Data Interchange File) file for both read and write operations, with certain limitations.

For read operations the supported vector entities are

• 3DFACEs
• ATTDEFs
• ATTRIBs
• LINEs
• MLINEs
• POINTs
• POLYLINEs
• SOLIDs
• TRACEs
• RAYs
• XLINEs

NOTE that POLYLINEs 2D with a START POINT, END POINT, and RADIUS are not supported.

ARCs, CIRCLEs and ELLIPSEs are supported by approximating them with line segments.

TEXTs and MTEXTs are also supported: the character string is stored in the "TextString" attribute and the orientation in the "Angle" attribute.

The non-vector entities, INSERT and BLOCK are supported.

On version 14, the definition of new Entity type (CLASSES SECTION) is supported, for all vector type read.

In read access, a Representation Table (RST) is built based on the drawing information that is available (line width, LTYPEs, etc.). Since this table is built while reading the file, it should be queried only after the file has been completely read in. Each entity read is given a "REPCode" attribute that points to an entry in this RST. Finally there is only one RST for the whole file, even if there are several layers.

Export of AutoCAD DXF files is supported. AutoCAD DXF files are exported with a type of "DXF".

For write operations the only entities that are written out are LINE, POLYLINE, TEXT and POINT entities. Any ARC, CIRCLE or ELLIPSE entity that may have been read in will be written out as a series of approximating line segments.

It is also possible to provide an RST when exporting. In this case the line types will be set in the new file. An entity with only 1 node and a "TextString" attribute will be written with the type TEXT, with or without an RST.